Max and Caroline laugh it up here as they listen to Han taling to his mother in Korea. We guess that's funny.
Added:

2 Broke Girls Season 1 Episode 20 Quotes

Max: Are you sure you didn't represent the woman who ate her child?
Leo: I've never represented anyone who ate their child ... on 'Law & Order.'

I was not talking hot. I was apologizing. She's still angry I left home. She thinks I'm freewheeling American who takes drugs and has intercourse with dirty Kardashians.

Han